At the present time there exist several patents relating to boxes made from various kinds of plastic materials which are designed to offer advantages and, at the same time, have the intention of eliminating shortcomings of other designs.
One example of such a box made using blown or injected plastic is Mexican Pat. No. 91,634, which has an exterior shape in the form of a parallelepiped with openings in the upper face to receive bottles and with cavities in the bottom to receive therein the caps of bottles placed in a similar lower box when the boxes are stacked upon each other. These boxes have a severe disadvantage in that, because the bottoms of the boxes are closed, it is difficult to clean or drain liquids which may get into the boxes. In addition, they are brittle and cannot be repaired.
Another embodiment of a box intended as an improvement is shown in Mexican Pat. No. 108,110, in which the partitions forming cells for the bottles are placed in a zig-zag fashion and the partitions are extended upwardly above the bottles in order to form a handle. Although this formation facilitates handling of the box, it makes it impossible to stack the boxes which is very inconvenient in locations such as plants and warehouses.
Another form of box is shown in Mexican Pat. No. 109,292, the height of which is equal to that of the bottles to be stored. In this box, the side walls wholly cover the bottles and, when they are stacked, the upper edge of the lower box makes contact with the lower edge of the upper box. The disadvantage in this box is that a great deal of material is necessary to make the boxes and, consequently, the cost thereof is high. Additionally, they occupy a great deal of space even when empty and this makes it more difficult to transport the boxes in an empty condition.
Still further, there are boxes of specific designs to be used, for example, in combination with certain machinery as illustrated by Mexican Pat. Nos. 140,875 and 116,501, but these containers are based upon ideas and functions not corresponding to the goals of the present invention.
A further form of boxes for bottles which is intended to eliminate all of these shortcomings includes openings at the bottom of the box which facilitates cleaning and at the same time avoids accumulation of liquids in the bottom. The lateral walls are low compared to the bottles so that when the boxes are piled up, they do not rest on the walls, but rather rest on the caps or tops of the bottles which are provided in a lower box. However, this form of box can have serious disadvantages. One is that as they are made of plastic material and as this is generally a smooth polished material, the boxes tend to slip, particularly when they are resting upon bottles covered with metal caps. The caps are also polished, and the boxes tend to slip, particularly when carried in trucks, raising a serious risk. In order to overcome this disadvantage, it has been suggested to place round pieces of rubber around the periphery of the box bottoms (Mexican Pat. No. 76,520) with the intention that when a box is placed upon another box, the caps of the bottles in the lower box contact the rubber pieces, thus avoiding possible slipping. This is not an effective solution because it does not effectively eliminate such slipping.
Another solution to this inconvenience consists in making holes in the bottom of the boxes to receive the bottle caps of bottles held in a lower box to avoid the slipping. However, this system is not effective and it has been proven in use that when a box filled with bottles is removed from the top of a stack, particularly when the stack is of a height on the order of a meter, the workers removing the box pull it in order to carry it away and, with this motion, in view of the fact that the caps protrude into holes in the bottom of the top box, there is a risk of the bottles being broken at the collar or a risk that caps are pried away, resulting in damage to the bottles and the material therein.
It has been suggested to overcome this problem by making wide and shallow holes at the box bottoms, intending to obtain a good hold between boxes and bottles and to promote ease of separation when necessary without the risk of breaking the bottles. However, because these holes are of a relatively large diameter and can permit the introduction into the upper box of almost all the neck of the bottle, the purpose sought is jeopardized. In order to avoid this advantage on the upper part of the hole, there have been provided ribs which may have several forms, such as a cross, a star, radial ribs, and the like. These ribs do not permit the bottles to protrude very much into the upper box but, at the same time, there is a weakness in the bottom of the box and for this reason the ribs tend to break, particularly when several boxes with filled bottles are stacked upon each other. It will be recognized that in such a case the lower boxes will carry the entire weight entirely upon those ribs which are simply insufficiently strong to hold this weight and therefore break, particularly if the stack of boxes is carried upon a bouncing truck.